The tear film’s oil layer, explained

The surface of your eye is covered by a thin tear film. Its outermost part is an oil layer, also called the lipid layer, and its job is to slow the evaporation of the watery layer underneath. Quell is designed around that outer layer, which is also where its emu oil comes in.

Two layers that matter here

Descriptions of the tear film usually begin with the watery, or aqueous, layer that keeps the surface of the eye moist. Above it sits the lipid layer: the outermost barrier of the tear film, responsible for minimizing evaporation of the aqueous layer.

That oil is made by small glands along the edges of the eyelids, and the oily substance itself is called meibum. What meibum is goes into more detail.

When the oil layer runs thin

Quell’s carton shows a before and after. Before: Water (Aqueous) Layer evaporates due to thin, unhealthy oil (Meibum) layer. After: Quell reinforces the tear film’s oil layer to help reduce moisture loss.

Everyday conditions add pressure. Concentrating on a screen cuts how often you blink, and your tear film evaporates while you stare. Wind and altitude outdoors, and air conditioning and central heat indoors, pull moisture off your eyes faster than you can replace it.

Water versus oil

Most drops top up the water layer. Quell reinforces the lipid layer above it, which is what slows evaporation down. The formula is designed to reinforce the eye’s natural lipid layer, and it is rich in bioactive fatty acids and botanical antioxidants, which support a more stable tear film.

So it pairs two lubricants with an emollient, light mineral oil, and a set of natural oil-based ingredients, instead of being a plain watery solution. That mix is also where the milky color comes from.

Where emu oil comes in

Emu oil is an all natural oil used by the Aboriginal people of Australia for thousands of years to nourish and protect the body. In artificial tears, it provides soothing support of the tear film’s oil layer to reduce moisture loss.

It is also behind the slogan on the box, “give your dry eye the bird,” and it is a large part of why the drop looks the way it does. The eye drops have a naturally milky-brown appearance. This is normal and does not indicate a problem with the product.

What the label says it is for

The science is the reasoning behind the formula. What the product is officially for is in the Uses section of the Drug Facts panel: For use as a protectant against further irritation or to relieve dryness of the eye.

Because the formula contains emu oil, read the first warning on the panel before your first bottle: Caution should be used in those with egg or bird allergies — For use in the eyes only.

Who developed it

Quell is a patented formula developed by a physician, built around how the tear film actually fails. It is sold by Aurora Pharmaceuticals, LLC of Brentwood, Tennessee.

Finding out more

If you want to know whether your symptoms fit the pattern of a tear film that evaporates too quickly, the dry eye self-check takes about ninety seconds. It is not a diagnosis and no substitute for an eye exam. When you are ready, see prices and buy.